The wrapping of articles in plastics resin film is commonplace. Often, articles are wrapped in center folded film, with a hot wire sealer being employed to seal and cut the individual packages, as they are formed sequentially. This seal forms the back seal of the leading package and the front seal of the trailing package. A seal must also be formed along the open side edge opposite from the center fold.
With many films, such as polyethylene, polypropylene, and other similar materials, this side seam may also be formed by a hot wire sealer. The sealer forms a bead-like seal closely adjacent to the article being packaged and simultaneously trims excess film from the edge of the package.
Some plastics resin films, notably polyvinyl chloride films, do not react well to hot wire sealing, especially continuous hot wire sealing as is necessary along side seams. Such films exhibit smoke and build-up on the hot wire sealing and cutting surface. There is a need, therefore, for a reliable system for forming side seals on plastic resins films, such as polyvinyl chloride film, which do not react favorably to continuous hot wire sealing.